1. Field of the Invention
This invention relates to a connector for optical fibers.
2. Description of the Prior Art
In an optical fiber connector, in order to reduce connection loss it is important to minimize the mismatch of mutual ends of the optical fibers to be connected by maintaining a high degree of concentricity of the optical fibers. Previously, it has been proposed to achieve the desired concentricity by employing fiber-retaining ferrules in the connector shells and an adaptor which included an alignment sleeve having a longitudinal slit. When the ferrule of the plug connector is inserted into the adaptor, a spring force is generated by the split sleeve and this force was designed to maintain the ferrules concentric to each other, even when the ferrules faced each other in a slanting angle.
It has been found, however, that such conventional connectors exhibited increasingly high connection losses as the number of insertions and extractions were increased. Further, it has been found that the connection losses were greatly different depending upon into which end of the adaptor the plug connector was inserted.
It would be desirable to eliminate these shortcomings in order to achieve stable signal transmission passage.